The general objective of this research is to assess the impact on relative wages of changes in the age, education, sex and race composition of the U.S. labor force. There are three specific objectives: (1) To discriminate between two completing explanations of why the wages of young workers fell relative to the wages of older workers in the 1970s. (2) To assess changes in relative wages across sexes and races in the 1970s and to determine whether such changes stem from changes in the demographic composition of the labor force. (3) To begin an analysis of the role of demographic structure in migration and regional growth. In our previous research we have developed a model which is particularly appropriate for the analysis of demographic effects on labor markets. We now seek to take advantage of our previous experience and the availability of additional data to confirm previous results and apply the model to new questions about the relationship between demographic composition and relative wages.